Document separating and feeding apparatus



Oct. 18, 1966 J. M STEINKE ETAL 3,279,790

- DOCUMENT SEPARATING AND FEEDING APPARATUS Filed Jan. 18, 1965 2 Sheets-Sheet 1 :iII

INVENTORS JAMES M. STEINKE Bu CHESTER A. ALBOSTA THEIR ATTORNEYS.

Oct. 18, 1966 J. M. STEINKE E' I'AL 3,279,790

- DOCUMENT SEPARATING AND FEEDING APPARATUS Filed Jan. 18, 1965 2 Sheets-Sheet 2 FIG. 2

w INVENTORS N 1 Q I JAMES M. STEINKE a CHESTER A. ALBOSTA BY m.

THEIR ATTORNEYS United States Patent 3,279,790 DOCUMENT SEPARATING AND FEEDING APPARATUS James M. Steinke and Chester A. Albosta, Dayton, Ohio, assignors to The National Cash Register Company, Dayton, Ohio, a corporation of Maryland Filed Jan. 18, 1965, Ser. No. 426,160 8 Claims. (Cl. 271-41) This invention relates to document feeding means and more particularly to a document feeding device for separating and advancing a single document fro-m a stack of documents upon command at a synchronous cyclic rate at high speed.

It is one of the objects of the invention to provide a document feeding device capable of singly or continuously separating and advancing a single document from a stack of documents upon external command.

It is another object to provide a mechanically synchronous document feeding device operating at high speed and capable of separating and advancing a single document from a stack of documents upon command.

It is still another object to provide a low cost, high speed controlled document feeding device capable of singly or continuously feeding documents on a cyclic basis wherein the device establishes the planar reference of the stack to act on the bottommost card. Instead of using vacuum, or any other means, to position the 'bottommost document, the devices feed head seeks out the bottom of the document stack to provide its own calibration for separating and advancing a single document.

In accordance with one aspect of the present invention, a document feeding apparatus is provided having a feed head including a knife carrier and a knife blade. Oscillatable means, which may comprise a bellcrank, is mounted below a hopper containing stacked documents. The feed head is pivotally mounted on the oscillatable means. There is provided means for oscillating said oscillatable means, and means for raising a lifting link towards said hopper during any oscillation of said oscillatable means whereby said document feed head is raised and said knife blade is moved in a path effective to cause separation and advancement of a single document from said hopper.

In accordance with another aspect of the present invention, the means for raising the lifting link comprises a lift arm having one end to Which the lifting link is pivotally connected, which end is biased in an initial position. The lift arm also has a normally free end. In addition, means are provided for displacing the lift arm at an intermediate position of its length during oscillation of the oscillatable means. The displacing means operates, when the free end of the lift arm remains free to move, to cause the lift arm to be pivoted at its connection to the lifting link whereby the knife blade is moved in a path ineffective to cause separation and advancement of a document. And, there is provided means for preventing movement of the free end of the lift arm during displacement of the lift arm so that the lift arm is pivoted at its free end and its other end is moved from its initial position causing the lift arm to move the lifting link towards the hopper whereby the feed head is raised and the knife blade is moved in another path effective to cause separation and advancement of a single document from the hopper.

Other objects and features of the present invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by Way of example, the principle of the invention and the best mode which has been contemplated of applying that principle.

In the drawings, in which like reference characters designate like components:

FIG. 1 is a perspective view of the document feeding apparatus comprising the present invention;

FIG. 2 is a side view of the document feeding apparatus shown in FIG. 1 in which its relationship with a hopper containing stacked documents is shown; and

FIG. 3 is a top view of the document feeding apparatus taken along the line AA of FIG. 2.

Referring now to the drawings, the document feeding device comprises an oscillatable feeder drive assembly 9 including a bellcrank 10 .pivotally supported on a fixed shaft or stud 13, a straight arm 11 pivotally supported at one end on the shaft 13 and spaced from the bellcrank 10, and another straight arm or link 12 having one end pivotally supported on the shaft 13 between the bellcrank 10 and the arm 11. A spacer 14 (FIG. 1) is mounted on the shaft 13 between the bellcrank 10 and the arm 11. A roller-follower 15 is mounted on a pin 16 between one of the ends 17 and 18 of the bellcrank 10 and arm 12 respectively. A knife carrier 19 having top, bottom, side and end portions is pivotally attached by one end portion to the bellcrank 10 and the arm 11 by means of a pin 20. The knife carrier 19 has a knife blade 23 attached to its other end portion by means of screws 24. The knife carrier 19 is provided with a central aperture 25 inside of which there is located a roller-follower 26 (FIG. 1) mounted on a pin 27. The pin 27 extends through and beyond the side portions of the knife carrier 19. A spring 30 is mounted between the pin 27 and a pin 31 located on the bellcrank 10. Another spring 32 is mounted between the pin 27 and a pin 33 located on the arm 11. The springs 30 and 32 bias the knife carrier 19 in a clockwise direction relative to its rotation about the pin 20.

A lifting link 34 is provided for rotating the knife carrier 19 counterclockwise about the pin 20. The lifting link 34 is mounted between the bellcrank 10 and the arm 11. One end of the lifting link 34 is pivotally attached to a fixed stud 35 which in turn is attached to a vertical support plate 21 (FIG. 3) of the document feeding device. The other end of the lifting link 34 is attached by means of a pivot pin 36 to a yoke portion comprising spaced arms 37 and 38 of a lift arm 39. The roller-follower 26 of the knife carrier 19 rests and rides on the top surface 40 (FIG. 1) of the lifting link 34, whose profile, in conjunction with the cam 47 profile determines the path of the knife 23 tip throughout the motion of the bellcrank 10. The lift arm 39 carries a pin 41 upon which is mounted a roller-follower 42. The lift arm 39 is provided with an upper flange portion 43 against which abuts a compreSsion spring 44. The compression spring 44 is mounted on a bracket 45, and an adjustment screw 46 is provided to adjust the pressure exerted by the spring 44 upon the lift arm 39. The spring 44 operates to maintain the roller follower 42 in contact with the cam surface of a lift cam 47. The lifting link 34 is provided with an adjustable screw 48 which rests against a fixed block 49. Adjustment of the screw 48 sets the initial non-separating attitude of the lifting link 34.

A rotatable cam shaft 50 has mounted thereon the lift cam 47, a drive cam 51 and a complementary cam 52. The roller-follower 42 on the lift arm 39 is held against the cam surface of the 'lift cam 47, the roller-follower 15 of the drive arm 10 and the link 12. is held against the cam surface of the drive cam 51, and a roller-follower 53 carried by a spring-follower arm 54 is held against the cam surface of the complementary cam 52.

The spring-follower arm 54 includes a long link 55 and a short link 56. The roller-follower 53 is carried on a stud 57 between the links 55 and 56. One end of each of the links 55 and 56 is pivotally attached to a stud 58, which in turn, is attached to the support plate 21. The other end of the short link 56 is attached to a stud 59 intermediate the ends of the long link 55. A high rate spring 60 is connected between the other end of the long link 55 and the drive arm 11 by means of the studs 61 and 62.

A11 L-shaped intenposer 63 is pivotally attached to a stud 64. An electromagnet 65 with its associated armature 66 is provided to move the interposer 63 clockwise against the urging of a spring 67. One end of the interposer 63 is normally held by means of the spring 67 away from the top surface of the end 390 of the arm-s 37 and 38 of the lift arm 39, while its other end is held against the end 6612 of the armature 66. The armature 66 is pivotable at its center on a stud 68. The end 66a of the armature 66 is attracted by the electromagnet 65' upon its energiz-ation, while its other end 66b is located between the interposer 63 and a stud 71 supported on a bracket 72 which is provided with an adjustment screw 7 3.

The document feeding device described above is capable of singly (during any cycle of the device) or continuously (during successive cycles of the device) separating and advancing a single document from a stack of documents 74 contained in a hopper 75 such as shown in FIGURE 3. The hopper 75 has a front wall 76, a rear wall 77, a bottom 78, and side walls (not shown). A middle portion of the rear wall 77 and the bottom 78 is provided with adjacent apertures '79 and 80 to accommodate the knife carrier 19 and its associated blade 23. The hopper 75 is provided with an exit throat 81 through which a document 74 is fed by the feeding device from the hopper to a first set of feed rollers 82 and 83.

The knife blade 23 is fastened to the knife carrier 19 with the lip 84 (FIG. 2) of the knife blade 23 extending above the knife carrier top surface just less than the thickness of two of the documents 74. The springs and 32 between the knife carrier 19 and the bellcrank 10 and the arm 11 hold the knife carrier roller-follower 26 against the top surface of the lifting link 34.

The operation of the separating and feeding device is as follows. With the cam shaft attached to a suitable drive source and rotating, the bellcrank 10 and the arm 11 will oscillate about the shaft 13 according to the acceleration and velocity curves predicted by the drive cam 51 thereby moving pivot pin 20 in a true are about the shaft 13 to the limits set by the high and low diameters of the drive cam 51. The knife carrier 19 will be carried by the pivot pin 20, and influenced in its relative attitude by the profile of the lifting link 34, since the rollerfollower 26 will be in contact with the top surface 40 thereof. The lip 84 of the knife blade 23 will therefore describe a path depending upon the configuration and geometry of the foregoing elements. If the adjustment or the screw 48 sets the path of the knife blade lip 84 below the document stack, then the lip 84 will pass freely in its arcuate path with no disturbance to the document stack. The screw 48 bears against a reference surface on the block 49, held in place by the compressive force of the spring 44.

During the rotation of the cam shaft 50, the free end of the lifting link 34 having established one set of coordinates for the pivot point at the. pivot pin 36, the lift arm 39 will move according to the displacement of the lift cam 47, which displacement will be amplified by the ratio of the length of the lift arm 39 to describe a path at its end 39a. When the interposer 63 intercepts the path of the end 39a of the lift arm 39, the end 39a itself becomes a fulcrum point, reflecting the displacement of the lift cam 47 to raise the pivot pin 36, thereby moving the lifting link 34 and consequently reestablishing the attitude of the contour of the lifting link top surface 40. Since the path of the knife carrier pivot pin 20 has already been established, the resultant path of the lip 84 of the knife 23 will raise behind the stack of documents 74, with the bottornmost document thereby being carried forward through the hopper throat 81 into the set of drive rolls 82 and 83.

A dwell portion is provided on the drive cam 51 for the action of the lift cam 47 to raise the knife carrier 19 into the document stack, so that the forward movement of the drive arms 10 and 11 is at essentially zero velocity. The forward motion of the knife carrier 19 will then obey the continuing profile of the drive cam 51 to permit a variety of desired accelerations and velocities.

In the preferred embodiment of the present invention, the drive cam 51 is provided with a half cycloidic cam rise portion which begins the forward acceleration of the knife carrier 19, a constant velocity portion which causes the knife carrier 19 to move forward at a constant velocity where insertion of a document into the matched velocity of the drive rolls 82 and 83 is insured, a half harmonic portion which reduces the forward motion of the knife carrier 19, a further half harmonic portion and a half cycloid portion effecting reverse or backward motion of the knife carrier 19 to its dwell attitude as provided by the dwell portion of the drive cam 51. During the full excursion of the foregoing cycle, the constant force of the spring 44 assures the exact displacement of the drive arm 10 because of the complementary surface of the spring-follower cam 52.

In the above-described device, the drive cam 51 and the lift cam 47 are fastened to a common shaft 50 providing mechanical synchronization, and the cam surfaces are generated to accomplish the desired path and timing of the tip of the knife blade 23. The complementary cam 52 is also fastened on the common shaft 50. The complementary cam 52 operates to complement the drive cam 51 so that the distance between the respective spring carrying pins 31 and 33 of the bellcrank 10 and the arm 11 is essentially constant during operation of the document feeding apparatus. This latter arrangement permits a minor deviation in the perfection of the surfaces of the cams 51 and 47 and still overcomes the tendency for the roller-followers 15 and 42 to leave their respective cams.

As pointed out heretofore, a dwell is provided at the beginning of the document separating and advancing cycle during which time a set function takes place. It is during this dwell where no forward motion of the knife carrier 19 is initiated that the knife carrier 19 raises the stack of documents to ensure that it is in intimate contact with the top surface of the knife carrier 19 with the knife blade 23 directly behind the back edge of the bottomrnost document. The greatest amount of time available is therefore given to allow the stack to settle against the forward wall reference surface of the hopper. The advantage of the foregoing arrangement of parts allows the knife blade to pass under the document stack on all return portions of the cycle or on non-separating and ad vancing forward strokes. Properly generated drive cams separate or pick each document at essentially zero forward velocity and provide acceleration of the document to the matching velocity of the feed rollers 82 and 83.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention.

It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. A document feeding apparatus for singly or continuously separating and advancing a single document from a hopper containing stacked documents comprismg:

(a) a document feed head including a knife carrier and a knife blade,

(b) oscillatable means mounted below said hopper, said document feed head being pivotally mounted on said oscillatable means,

(0) a lifting link having one end pivotally mounted in a fixed position, and having a top surface on which said feed head is adapted to ride during oscillation of said oscillatable means,

(d) a lift arm having one end to which the other end of said lifting link is pivotally connected biased in an initial position, and having a normally free end,

(e) means for oscillating said oscillatable means,

(f) means for displacing said lift arm at an intermediate position of its length during oscillation of said oscillatable means, said means for displacing said lift arm operating, when said free end of said lift arm remains free to move, to cause said lift arm to be pivoted at its connection to said lifting link whereby said knife blade is moved in a path ineffective to cause separation and advancement of a document, and

(g) means for preventing movement of said free end of said lift arm during displacement of said lift arm so that said lift arm is pivoted at its free end and its other end is moved from said initial position causing said lift arm to move said lifting link towards said hopper whereby said document feed head is raised and said knife blade is moved in another path effective to cause separation and advancement of a single document from said hopper.

2. A document feeding apparatus for singly or continuously separating and advancing a single document from a hopper containing stacked documents comprismg:

(a) a document feed head including a knife carrier and a knife blade,

(b) oscillatable means mounted below said hopper, said document feed head being pivotally mounted on said oscillatable means,

(0) a lifting link having one end pivotally mounted in a fixed position, and having a top surface on which said feed head is adapted to ride during oscillation of said oscillatable means,

(d) means connected between said oscillatable means and said feed head urging said feed head against the top surface of said lifting link,

(e) a lift arm having one end to which the other end of said lifting link is pivotally connected biased in an initial position, and having a normally free end,

(f) means for oscillating said oscillatable means,

(g) means for displacing said lift arm at an intermediate position of its length during oscillation of said oscillatable means, said means for displacing said lift arm operating, when said free end of said lift arm remains free to move, to cause said lift arm to be pivoted at its connection to said lifting link whereby said knife blade is moved in a path ineffective to cause separation and advancement of a document, and

(h) means for preventing movement of said free end of said lift arm during displacement of said lift arm so that said lift arm is pivoted at its free end and its other end is moved from said initial position causing said lift arm to move said lifting link towards said hopper whereby said document feed head is raised and said knife blade is moved in an other path effective to cause separation and advancement of a single document from said hopper.

3. A document feeding apparatus for singly or continuously separating and advancing a single document from a hopper containing stacked documents comprising:

(a) a document feed head including a knife carrier and a knife blade,

(b) oscillatable means mounted below said hopper, said document feed head being pivotally mounted on said oscillatable means,

(c) a lifting link having one end pivotally mounted in a fixed position, and having a top surface on which said feed head is adapted to ride during oscillation of said oscillatable means,

(d) means connected between said oscillatable means and said feed head urging said feed head against the top surface of said lifting link,

(e) a lift arm having one end to which the other end of said lifting link is pivotally connected and having a normally free end,

(f) means urging said end of said lift arm to which the other end of said lifting link is pivotally connected in an initial position,

(g) means for oscillating said oscillatable means,

(b) means for displacing said lift arm at an intermediate position of its length during oscillation of said oscillatable means, said means for displacing said lift arm operating, when said free end of said lift arm remains free to move, to cause said lift arm to be pivoted at its connection to said lifting link whereby said knife blade is moved in a path ineffective to cause separation and advancement of a document, and

(i) means for preventing movement of said free end of said lift arm during displacement of said lift arm so that said lift arm is pivoted at its free end and its other end is moved from said initial position causing said lift arm to move said lifting link towards said hopper whereby said document feed head is raised and said knife blade is moved in another path effective to cause separation and advancement of a single document from said hopper.

4. A document feeding apparatus for singly or continuously separating and advancing a single document from a hopper containing stacked documents comprising:

(a) a document feed head including a knife carrier and a knife blade,

(b) oscillatable means mounted below said hopper, said document feed head being pivotally mounted on said oscillatable means,

(0) a lifting link having one end pivotally mounted in a fixed position, and having a top surface on which said feed head is adapted to ride during oscillation of said oscillatable means,

(d) a lift arm having one end to which the other end of said lifting link is pivotally connected biased in an initial position, and having a normally free end,

(e) means for oscillating said oscillatable means,

(f) means for displacing said lift arm at an intermediate position of its length during oscillation of said "oscillatable means, said means for displacing said lift arm operating, when said free end of said lift arm remains free to move, to cause said lift arm to be pivoted at its connect-ion to said lifting link whereby said knife blade is moved in a path ineffective to cause separation and advancement of a document,

(g) means for preventing movement of said free end of said lift arm during displacement of said lift arm so that said lift arm is pivoted at its free end and its other end is moved from said initial position causing said lift arm to move said lifting link towards said hopper whereby said knife blade is moved in another path effective to cause separation and advancement of a single document from said hopper, and

(h) said last-mentioned means comprising an interposer member and an electromagnet, with said interposer member being moved into inter-posing relationship with the free end of said lift arm upon energization of said electromagnet. 5. A document feeding apparatus for singly or continuously separating and advancing a single document from a hopper containing stacked documents comprising:

(a) a document feed head including a knife carrier and a knife blade,

(b) oscillatable means comprising a bellcrank pivotally mounted below said hopper, said document feed head being pivotally mounted on one end of said bellcrank,

(c) a lifting link having one end pivotally mounted in a fixed position, and having a top surface on which said feed head is adapted to ride during oscillation of said oscillatable means,

(d) a lift arm having one end to which the other end of said lifting link is pivotally connected biased in an initial position, and having a normally free end,

(e) means for oscillating said bellcrank,

(f) means for displacing said l-ift arm at an intermediate position of its length during oscillation of said oscillatable means, said means for displacing said lift arm operating, when said free end of said lift arm remains free to move, to cause said lift arm to be pivoted at its connection to said lifting link whereby said knife blade is moved in a path ineffective to cause separation and advancement of a document, and

(g) means for preventing movement of said free end of said lift arm during displacement of said lift arm so that said lift arm is pivoted at its free end and its other end is moved from said initial position causing said lift arm to move said lifting link towards said hopper whereby said document feed head is raised and said knife blade is moved in another path effective to cause separation and advancement of a single document from said hopper.

6. A document feeding apparatus for singly or continuously separating and advancing a single document from a hopper containing stacked documents comprising:

(a) oscillatable means comprising a bellcrank pivotally mounted below said hopper and carrying a rollerfollower at one end thereof,

(b) a document feed head including a knife carrier and a knife blade, said knife carrier having top, bottom and end portions, one end portion of said knife carrier being pivotally connected between the other end of said bellcrank and its other end portion having said knife blade attached thereto, said knife carrier containing a roller-follower between its end portions,

() a lifting link having one end pivotally mounted in a fixed position, and having a top surface on which the roller-follower of said knife carrier is adapted to ride during oscillation of said oscillatable means,

(d) a lift arm having one end to which the other end of said lifting link is pivotally connected biased in an initial position, and having a normally free end,

(e) means coacting with the roller-follower of said bellcrank for oscillating said bellcrank,

(f) means for displacing said lift arm at an intermediate position of its length during oscillation of said oscillatable means, said means for displacing said lift arm operating, when said free end of said lift arm remains free to move, to cause said lift arm to be pivoted at its connection to said lifting link whereby said knife blade is moved in a path ineffective to cause separation and advancement of a document, and

(g) means for preventing movement of said free end of said lift arm during displacement of said lift arm so that said lift arm is pivoted at its free end and its other end is moved from said initial position causing said "lif-t arm to move said lifting link towards said hopper whereby said document feed head is raised and said knife blade is moved in another path effective to cause separation and advancement of a single document from said hopper. 7. A document feeding apparatus for singly or continuously separating and advancing a single document from a hopper containing stacked documents comprising:

(a) a document feed head including a knife carrier and a knife blade,

(b) a rotatable drive shaft carrying a drive cam and a lift cam,

(c) oscillatable means mounted below said hopper, said document feed head being pivotally mounted on said oscillatable means and carrying a roller-follower riding on the cam surface of said drive cam,

(d) a lifting link having one end pivotally mounted in a fixed position, and having a top surface on which said feed head is adapted to ride during oscillation of said oscillatable means,

(e) a lift arm having one end to which the other end of said lifting link is pivotally connected biased in an initial position, having a normally free end, and carrying a roller-follower intermediate its length riding on the cam surface of said lift cam, rotation of said drive shaft causing said drive cam to oscillate said oscillatable means, and said lift cam to displace said lift arm during oscillation of said oscillatable means, displacement of said lift arm operating, when said free end of said lift arm remains free to move, to cause said lift arm to be pivoted at its connection to said lifting link whereby said knife blade is moved in a path ineffective to cause separation and advancement of a document, and

(f) means for preventing movement of said free end of said lift arm during displacement of said lift arm so that said lift arm is pivoted at its free end and its other end is moved from said initial position causing said lift arm to move said lifting link towards said hopper whereby said document feed head is raised and said knife blade is moved in another path effective to cause separation and advancement of a single document from said hopper.

8. A document feeding apparatus for singly or continuously separating and advancing a single document from a hopper containing stacked documents comprising:

(a) a document feed head including a knife carrier and a knife blade,

(b) a rotatable drive shaft carrying a drive cam, a cam complementary to said drive cam and a lift cam, (c) oscillatable means mounted below said hopper, said document feed head being pivotally mounted on said oscillatable means and carrying a roller-follower riding on the cam surface of said drive cam,

(d) a lifting link having one end pivotally mounted in a fixed position, and having a top surface on which said feed head is adapted to ride during oscillation of said oscillatable means,

(e) a lift arm having one end to which the other end of said lifting link is pivotally connected biased in an initial position, having a normally free end, and carrying a roller-follower intermediate its length riding on the cam surface of said lift cam,

(f) a follower arm having one end pivotally mounted in a fixed position and another free end, said follower arm carrying a roller-follower intermediate its length riding on the cam surface of said complementary cam,

(g) spring means connected between the free end of said follower arm and said oscillatable means urging the roller-follower of said follower arm against the cam surface of said complementary cam, rotation of said drive shaft causing said drive cam to oscillate said oscillatable means, said lift cam to displace said lift arm, and said complementary cam to ensure that the roller-followers carried by said oscillatable means and said lift arm do not leave the cam surfaces of said drive cam and said lift cam during operation of said feeding apparatus, displacement of said lift arm operating, when said free end of said lift arm remains free to move, to cause said lift arm to be pivoted at its connection to said lifting link whereby said knife blade is moved in a path ineffective to cause separation and advancement of a document, and

10 hopper whereby said document feed head is raised and said knife blade is moved in another path effective to cause separation and advancement of a single document from said hopper.

References Cited by the Examiner (h) means for preventing movement of said free end of said lift arm during displacement of said lift arm 2 632 644 so that said lift arm is pivoted at its free end and its 2:880:996 other end is moved from said initial position causing 10 said lift arm to move said lifting link towards said UNITED STATES PATENTS 3/1953 Wockenfuss et a1. 27144 4/1959 Stiles 271-44 SAMUEL F. COLEMAN, Primary Examiner. 

1. A DOCUMENT FEEDING APPARATUS FOR SINGLY OR CONTINUOSULY SEPARATING AND ADVANCING A SINGLE DOCUMENT FROM A HOPPER CONTAINING STACKED DOCUMENTS COMPRISING: (A) A DOCUMENT FEED HEAD INCLUDING A KNIFE CARRIER AND A KNIFE BLADE, (B) OSCILLATABLE MEANS MOUNTED BELOW SAID HOPPER, SAID DOCUMENT FEED HEAD BEING PIVOTALLY MOUNTED ON SAID OSCILLATABLE MEANS, (C) A LIFTING LINK HAVING ONE END PIVOTALLY MOUNTED IN A FIXED POSITION, AND HAVING A TOP SURFACE ON WHICH SAID FEED HEAD IS ADAPTED TO RIDE DURING OSCILLATION OF SAID OSCILLATABLE MEANS, (D) A LIFT ARM HAVING ONE END TO WHICH THE OTHER END OF SAID LIFTING LINK IS PIVOTALLY CONNECTED BIASED IN AN INITIAL POSITION, AND HAVING A NORMALLY FREE END, (E) MEANS FOR OSCILLATING SAID OSCILLATABLE MEANS, (F) MEANS FOR DISPLACING SAID LIFT ARM AT AN INTERMEDIATE POSITION OF ITS LENGTH DURING OSCILLATION OF SAID OSCILLATABLE MEANS, SAID MEANS FOR DISPLACING SAID LIFT ARM OPERATING, WHEN SAID FREE END OF SAID LIFT ARM REMAINS FREE TO MOVE, TO CAUSE SAID LIFT ARM TO BE PIVOTED AT ITS CONNECTION TO SAID LIFTING LINK WHEREBY SAID KNIFE BLADE IS MOVED IN A PATH INEFFECTIVE TO CAUSE SEPARATION AND ADVANCEMENT OF A DOCUMENT, AND (G) MEANS FOR PREVENTING MOVEMENT OF SAID FREE END OF SAID LIFT ARM DURING DISPLACEMENT OF SAID LIFT ARM SO THAT SAID LIFT ARM IS PIVOTED AT ITS FREE END AND ITS OTHER END IS MOVED FROM SAID INITIAL POSITION CAUSING SAID LIFT ARM TO MOVE SAID LIFTING LINK TOWARDS SAID HOPPER WHEREBY SAID DOCUMENT FEED HEAD IS RAISED AND SAID KNIFE BLADE IS MOVED IN ANOTHER PATH EFFECTIVE TO CAUSE SEPARATION AND ADVANCEMENT OF A SINGLE DOCUMENT FROM SAID HOPPER. 